#include <iostream>

using namespace std;

namespace A
{
	const char* const str1 = "A1";
	const char* const str2 = "A2";
}

namespace B
{
	const char* const str1 = "B1";
	const char* const str2 = "B2";
}

int main()
{
	{
		using namespace A;
		cout << str1 << "," << str2 << endl;
	}

	{
		using namespace B;
		cout << str1 << "," << str2 << endl;
	}

	return 0;
}